MOSCOW — Russian authorities on Saturday announced that they had identified a 20-year-old native of the North Caucasus region as the suicide bomber who killed 35 people at Domodedovo Airport’s international arrivals hall — a location chosen specifically because it gave the opportunity to kill foreigners.

They did not announce the man’s name, saying that the authorities were seeking to detain “organizers and accomplices” who were involved in the attack.

Concentrating on foreigners would be a departure for the insurgency — though foreigners have previously been caught in mass attacks, such as the 2002 siege of a Moscow theater, there has never been any suggestion that they were the target.

But militants in North Caucasus have already made it clear they are changing their tactics to include high-profile attacks on civilians. The vast majority of insurgent attacks still target the police and other state officials in the tumultuous southern region, one that has long chafed under Moscow’s control. But the militant leader Doku Umarov last year warned the residents of central Russia that “the war come to your streets.”

The vow was borne up by a November 2009 bombing on a luxury train on its way to St. Petersburg and a double suicide bombing in March in the Moscow subway. The airport bombing — at a glittering showcase facility on the eve of President Dmitry Medvedev’s speech at the World Economic Forum — appears specifically geared to attract global attention.

Among the factors driving the Caucasus militants to stage dramatic attacks is a generational shift, as veterans of the secular Chechen separatist movement are replaced by younger men who are adherents of fundamentalist Islam, said Mark Galeotti, a specialist in Russian security issues who leads New York University’s Center for Global Affairs.

“There’s a sense that the West isn’t going to care about us, so why are we bothering being cautious,” Galeotti said. “When foreigners get killed, it’s more of a news story, and also it’s more embarrassing for Moscow — given that the rebels are already revving themselves up to do something at Sochi,” where Russia is hosting the Olympics in 2014.

The investigative committee offered no information about the bomber other than his age and origins. Video of the site of the bombing showed that he stood for as long as 15 minutes in a crowd of people waiting to greet passengers disembarking from international flights.

Among those killed were citizens of Britain, Ukraine, Germany, Austria, Uzbekistan, Tajikistan and Kyrgyzstan.

The announcement also put to rest speculation that Monday’s bombing was connected with an incident that occurred Dec. 31, when a building rented from a Moscow hotel blew up in what appeared to be a botched suicide attack. Searching the premises the police found traces of a store of explosives, a woman’s body and a suicide bomber’s belt.

Investigators believe a separate cell was planning a separate attack in downtown Moscow that night, the statement says.

“The terrorist attack at Domodedovo and the explosion in the hotel complex were carried out by unrelated armed groups, existing in different republics of the North Caucasus,” the statement said.